This invention relates to plasma firing mechanism for firearms, methods for firing firearms, and methods for controlling the firing of firearms. In a particular embodiment, the mechanism or device more effectively controls and/or manages the rate of fire and the number of rounds fired for automatic firearms.
Historically, semiautomatic and automatic weapons used mechanical percussion to fire a conventional cartridge comprising a primer or a casing containing a quantity of gunpowder or other explosive or propellant material. The casing is typically cylindrical in shape with a bullet that is initially lodged in one end of the cartridge and a primer located in the opposite end. A mechanism for detonating the primer typically includes a hammer and firing pin propelled by the force of a spring or other suitable mechanism. The movement of the hammer and the firing pin is initiated by pulling the trigger. The inertia of the hammer and firing pin introduces a time lag, sometimes called lock time, between the trigger pull and detonation of the primer. The percussion primer detonates when struck by the firing pin, igniting the gunpowder and ejecting the bullet from the cartridge under the pressure created by the expanding gases created by the exploding gunpowder.
The use of a mechanical firing pin creates a risk that the firing pin may strike the primer too hard and penetrate the primer. This creates a path for the expanding gases to escape through the breach in the primer, which reduces the pressure available to propel the bullet and increases the chance of injury to the operator or damage to the weapon. Mechanical firing systems are also subject to wear with subsequent deterioration of performance.
In order to fire multiple rounds of ammunition, a percussion and reload cycle is established, wherein the spent casing is removed from the firing chamber, a fresh round of ammunition is chambered, and the firing pin strikes the primer of the fresh round of ammunition to repeat the process. For semiautomatic weapons, the movement of the firing pin is initiated by successive pull and release of a trigger, with a single round being fired for each pull of the trigger. For automatic weapons, a single pull of the trigger causes the firing pin to strike the primer of each successive round of ammunition without further operator interaction. The rates of fire of such conventional automatic weapons generally are a function of the time it takes for the percussion and reload cycle to be completed. The length of this cycle is largely a function of the time it takes for the mechanical parts to move through their range of motion.
Once the mechanical parts and ammunition are selected for a particular firearm design, the firing rate typically is set and cannot be adjusted by the operator. Moreover, the practical maximum firing rate for automatic weapons is limited by the cycle time of the mechanical parts. This may be disadvantageous in certain circumstances because a reduced number of rounds may be placed on a fast moving target before it moves out of range of the automatic weapon, leading to a lower target hit rate.
In certain circumstances, fully automatic firing can lead to excessive ammunition use without a corresponding increase in target kill rate and, thus, the depletion of available ammunition on a particular sortie. One solution to this problem is to employ a lower rate of fire to limit the excessive use of ammunition. Alternatively, a burst firing mode can be used wherein a single trigger pull causes a set number of rounds to fire, rather than continuing to fire ammunition until the trigger is released, as is the case in conventional fully automatic weapons. The number of rounds fired in burst firing mode is typically also a function of the action of the mechanical parts of the weapon and thus cannot be varied by the operator. Because the firing of successive rounds occurs without operator interaction or control, the operator is unable in conventional systems to select the precise timing of firing any particular round or to vary the firing rate in other situations.
Other types of priming systems exist and others have been proposed, especially for large caliber artillery ammunition and aircraft and watercraft armaments. In the case of aircraft armaments in particular, one alternative to mechanical percussion is electrical percussion, which is used with electrical primer ammunition. In an electrical percussion system, the mechanical firing pin is replaced by an electrically conductive firing pin that makes good electrical contact with an electrical primer prior to initiating a firing sequence. The electrically primed cartridges have an electrically conductive portion that is grounded electrically to the walls of the firing chamber. One serious drawback of electric percussion is the requirement for specialized ammunition with embedded electrodes. Conventional primer initiated ammunition will not work in a weapon designed for electric percussion and the specialized ammunition with embedded electrodes will not work with conventional weapons. This prevents interoperability or sharing of ammunition and complicates logistics for supply of military units that employ both conventional and electric percussion weapons.
Another possible alternative to mechanical primed ammunition, particularly in the artillery context, is laser-fired ammunition. For laser-fired artillery systems, the projectile and propellant are loaded in conventional fashion, but the mechanical primer and firing pin are replaced by a laser firing system that is typically integral to the breech block of the cannon. An optical window is provided in the breech block to allow the passage of high energy, pulsed laser light into the propellant chamber to directly ignite the propellant ignition pad and fire the projectile. The laser firing system eliminates the complexity and delays caused by the loading of a mechanical primer and mechanical percussion by the firing pin. However, laser firing systems (none of which have been placed into production) are generally expensive and require considerable development and manufacturing time when compared to mechanical primer systems. In addition, the optical viewing window of the laser system must be sealed against the pressure and heat of the propellant chamber while maintaining suitable optical properties. The combination of heat, pressure, and propellant residue from the propellant chamber and the laser energy passing through the viewing window can cause clouding, obscuration, and/or pitting of the viewing window over time, resulting in degraded performance of the laser ignition system.
Thus, the firing methods used in current firearms, aircraft and watercraft armaments, and artillery suffer from a number of deficiencies. For example, the rate of fire is predetermined by the selection of mechanical parts and the type of ammunition cannot be varied once the weapon is built. Maximum ring rate for a particular type of ammunition is limited by the cycle time of the mechanical parts. Once the weapon is designed and built the operator cannot control the firing rate, timing of firing a particular cartridge, or the number of rounds fired in burst mode. For these and other reasons, improvements in the design and operation of firing systems and methods for firing automatic weapons are needed.
In one aspect, the present invention provides improved devices for varying the firing rate, precisely controlling the firing of individual rounds of ammunition, and varying the number of rounds fired in burst mode. The invention is not limited to solving any particular problem or disadvantage. In addition, the invention is not limited to use with any particular size or type of ammunition. However, the advantages made available through the invention can be used with conventional mechanical primer initiated ammunition and/or in place of the mechanical primer and firing pin arrangement of the conventional firearm. xe2x80x9cFirearm,xe2x80x9d as used here, encompasses artillery, handguns, pistols, heavy caliber guns, rifles, sniper rifles, guns with automatic and semiautomatic action, mountable and portable cannons, cannons mounted on motor vehicles, aircraft, watercraft or naval vessels, cannons mounted on armored personnel carriers or other armored vehicles, and machine guns or cannons mounted on armored or non-armored vehicles or vessels. The terms xe2x80x9cfirearmxe2x80x9d and xe2x80x9cartilleryxe2x80x9d are used interchangeably here.
One aspect of the invention is to reduce and/or eliminate the lag time between initiating a firing sequence, by pulling a trigger or by other means, and detonation of the chambered round. The invention also facilitates the design and production of a more versatile weapon and/or allows the operator to vary the firing rate to suit the particular application or target. Because detonation is caused by a plasma torch or pulse of short duration, very high firing rates can be supported. In another aspect, the plasma firing mechanisms of the invention provide robust and reliable components that can be used in a variety of ammunition systems. Thus, incorporating one or more of the many aspects of the invention into a firearm improves the control and effectiveness of the firearm.
In another aspect, the present invention operates by using a plasma torch to detonate ammunition or a primer in a cartridge to fire a bullet or projectile in a controlled fashion. The plasma torch is generated by using an arc across a gap between a cathode and an anode. A high voltage pulse, a high current pulse, and pressurized gas or air flowing between the cathode and anode extends an arc into a plasma torch capable of contacting a primer, a surface of a cartridge, and/or a propellant charge. In a preferred embodiment, more than one voltage pulse or current pulse across the cathode/anode gap is used to significantly increase the energy of the plasma torch. The power supply may use a first generator to supply the voltage to create the initial arc and a second generator to supply the current pulse to generate the plasma torch. Alternately, a single generator capable of varying its voltage and current output may be used. Thus, one of skill in the art can substitute a variety of electrical elements to construct a suitable power supply for generating a plasma torch in accordance with the present invention.
In general, the devices and methods of the invention can function to create intense heat through the plasma torch, which can be used to cause a primer to fire, igniting the gunpowder or other primer or propellant within the cartridge, or to directly cause the propellant charge to fire. In certain operational circumstances, this will cause a bullet or projectile to be ejected and propelled along the barrel of the firearm by the expanding gases produced by the detonation.
One of skill in the art will understand that the arrangement of the anode and cathode, the voltage across the cathode/anode gap, the current across the anode/cathode gap, the pressure of the air or gas, the duration of the pulse(s), and anode/cathode gap or configuration can be adjusted. One of skill in the art can vary the length, size, temperature, and duration of the plasma torch. By appropriate adjustment of these parameters, the plasma firing device can be used to operate a wide range of ammunition, primers, artillery cannons, naval and aircraft guns, rifles, pistols, and machine guns.
In another aspect, the present invention can be used to render obsolete the mechanical primer and firing pin arrangement for cannons and artillery or vehicle mounted weapons. This reduces the length of the percussion reload cycle by eliminating the step of inserting the mechanical primer manually or mechanically. This alone can increase the maximum allowable firing rate of the weapon and improve operator safety by eliminating the need for personnel to handle mechanical primers. In preferred embodiments of the artillery or naval gun applications, parts of the plasma torch generator are preferably integrated into the breech of the weapon, with the power supply and air supply external to the harsh environment of the propellant chamber. Once the fuzed projectile and propellant are loaded, the breech is closed and the weapon is ready to fire. When the firing sequence is initiated, the plasma torch is generated in much the same fashion as described above. The introduction of the gas and high voltage and high current pulses can be precisely timed to fire the projectile. When initiated, the plasma torch extends into the propellant chamber, igniting the propellant and firing the projectile.
The invention comprising the use of a plasma torch is simpler, cheaper, and more durable than laser ignition devices and lacks the requirement for an optical window. The plasma firing device of the present invention also eliminates the delays and safety issues associated with manual or mechanical loading of percussion primers in conventional artillery or cannons.
In yet another aspect, the invention comprises a method for firing a firearm employing a plasma torch generator as well as method for generating and/or calibrating a plasma torch to fire a primer or round. For example, the invention encompasses a method for firing a primer or propellant charge by providing a plasma torch generator, where the plasma torch generator comprises a cathode, an anode, a gas passage for allowing pressurized gas to flow between the anode and cathode, and a power source electrically coupled to the anode and the cathode. In one preferred embodiment, a first voltage is applied between the anode and cathode to cause an arc to form. Pressurized gas is applied to the arc or to the gap between the anode and cathode via a gas passage. As used here, xe2x80x9cgasxe2x80x9d can be some inert gas or other gas that does not interfere with the generation of a plasma torch, or it can be air. A current is then applied to generate a plasma torch, wherein the plasma torch generator is positioned so that a plasma torch is capable of contacting a primer, a surface of a cartridge or ammunition, or a propellant charge. The order of the steps listed above, or elsewhere in the methods of this invention, need not necessarily be exactly the same as written. Similarly, the invention encompasses a method for calibrating a plasma torch generator to fire a primer or propellant charge. The method can comprise altering one or more of a number of factors involved in or known to be involved in generating a plasma torch. For example, the type of cathode or anode used, the gap between the cathode and the anode, the voltage used, the pressure of the gas or air, the duration of the plasma torch, the size of the plasma torch, the temperature generated on a surface in contact with the plasma torch, can all be varied to optimize, either one factor at a time or more than one factor, to generate a desired plasma torch. One of skill in the art is familiar with method and techniques to, vary each of these factors.
As described here, a preferred embodiment of the methods or devices of the invention employs one or more plasma torch generators capable of using a 5 to 10 msec pulse of current, for example, to generate a plasma torch. Additional preferred aspects include, for example, embodiments in which one or more of the plasma torch generators or operating with one or more generators: a vortex cathode; a continuous air flow over the cathode/anode of about 3 to about 5 bar; a pressurized air supply at about 3 to about 5 bar or from about 3 to about 10 bar; an initial arc generating voltage of between about 3 kV and about 20 kV; a torch generating a current pulse, or high current pulse, of approximately 15 amps, whereby a 85 V/15 amp pulse crosses the anode/cathode gap; a power source for generating an initial arc and a separate power source for generating a current pulse; a nickel plated copper cathode; a copper anode; a torch guide; a tungsten torch guide; and ceramic insulators.
The plasma torch generator, plasma firing device, and methods of the invention can be manifested as in one of the Figures accompanying this disclosure. Also, numerous embodiments and alternatives are disclosed in the accompanying claims. Other embodiments and advantages of the invention are set forth in part in the description that follows, and in part, will be obvious from this description, or may be learned from the practice of the invention.